When industrial-rated circuit breakers are connected within a lighting circuit breaker panelboard enclosure in a "double-branch" arrangement, wherein two opposedly adjacent circuit breakers are connected to the same branch strap, some means must be employed to prevent the exhaust gases emanating from one of the circuit breakers during an intense overcurrent fault from entering the opposing circuit breaker and causing a phase-to-phase fault within the panelboard enclosure. A double-branch arrangement of circuit breakers within a panelboard enclosure is described, for example, in U.S. Pat. No. 4,783,718 entitled "Lighting Circuit Breaker Panelboard Modular Assembly". When the circuit breakers are double-branch connected within the panelboard enclosure, additional electrical insulation is provided between the ends of the circuit breakers and the interior side walls of the enclosure to prevent a phase-to-ground fault caused by electrical circuit between the exhaust arc gases and the grounded enclosure.
When the circuit breakers are connected in a single branch arrangement whereby each circuit breaker is connected to a separate branch strap within an electrical enclosure, the line and load lugs on opposite sides of the circuit breakers are connected with the corresponding electrical power distribution cables. A unitary plastic support for a single branch circuit breaker arrangement is described within U.S. patent application Ser. No. 599,608 entitled "Single Branch Circuit Breaker Support". An insulative lug cover must be arranged over both ends of the circuit breakers to prevent inadvertent electrical contact.
One such lug cover is described for example, in U.S. patent application Ser. No. 546,826 filed Jun. 29, 1990 and entitled "Compact Molded Case Circuit Breaker with Increased Ampere Rating". The lug covers described therein, cooperate with an additional extension provided on the ends of the circuit breaker to mechanically support the lug covers.
It would be economically advantageous, to provide bus covers and lug covers for molded case industrial-rated circuit breakers which require no additional fastening means for holding the lug and bus covers to the circuit breaker enclosure. Accordingly, one purpose of the invention is to describe both lug and bus covers for industrial-rated circuit breakers which are economically feasible for both factory as well as field-installation.